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CHRISTOPHER COLUMBUS AT PALOS HARBOUR (CARTAGENA) THE ASTROLABE — NAVIGATIONAL TOOL
Pursuit of Nautical
Science
The same could be said of Portugal, which emerged as
a nation in 1128 after the Battle of São Mamede with the
defeat of the Moors. After the re-conquest of Portugal was
finalized in 1250 with victory over the south, Portugal began
a period of great development in navigation.
That development started with a faith in mathematics,
physics, oceanography and astronomy. Henry the Navigator,
the catalyst for Portuguese exploration and imperialism,
founded a town on Portugal’s southwest coast at Cape
St. Vincent called Vila do Infante — the Prince’s Town
— where he pursued advances that made transoceanic
navigation possible. It was a sublime place to nurture the
seeds of the Age of Exploration; and, it’s said cartographers
and astronomers were invited there to both develop and
improve the science of navigation.
History books are filled with the exploits of Portuguese
explorers. In 1488, Bartolomeu Dias became the first
European mariner to round the southern tip of Africa. He
was soon followed by Vasco da Gama, who in 1497 sailed
around the Cope of Good Hope and was the first European
to reach India by sea. In 1500 Pedro Álvares Cabral led an
expedition that ‘discovered’ the land that would later be
known as Brazil.
Instruments of
Exploration
The earliest periods of navigation within Portugal and Spain
involved the use of what we’d today consider crude and
unreliable instruments. The kamal and cross-staff, while
both useful in determining latitude, lacked the ability to be
consistently applied while at sea. They were replaced by
the trigonometric quadrant and its semi-circle construction.
This was an improvement but proved unreliable at times,
as calm waters were necessary to acquire a reading.
The quadrant was eventually used with the astrolabe and
became a critical piece of equipment for navigation after
Martin Cortes de Albacar, a Spanish cosmographer from
Aragon, published his Art of Navigation in 1551. It was
revolutionary in that it could be used day or night, in rough
or calm seas, and when used with the quadrant allowed
navigators to gain the most accurate readings possible.
Finally, the nocturnal and its accompanied values in the
ephemerides granted sailors the ability to plot longitude
on the open ocean. Weather and the tenuousness of
equipment made all trips perilous, but this evolution in
technology allowed explorers to be confident that a course
could be safely and accurately plotted from a port of call
to a final destination.
By the mid-16th-century, nautical sciences granted
humankind the ability to circumnavigate the globe, uncover
vast reserves of untouched natural resources, open dialogue
with previously unknown cultures, and open lucrative new
trading routes. The expansion of humanity’s connections
was well underway.
Joe Wall is an American writer who’s lived and worked in Australia, Fiji and New Zealand. His affinity for the word ‘mate’ appears permanent.